Re: [ptest-runner][PATCH 4/4v2] utils.c: wait_child reimplement timeout using alarm


Yi Fan Yu
 

On 3/24/21 2:40 PM, Aníbal Limón wrote:
[Please note: This e-mail is from an EXTERNAL e-mail address]
Since we are using threads to read from child, no complex logic is
needed for handle timeouts by std{out,err} in the child using alarm(2).
[YOCTO #14220]
Signed-off-by: Aníbal Limón <anibal.limon@...>
LGTM, solves my bug and my issue with the old timeout behaviour.

I tested glib-2.0 with the extra debugging output. It works.
Also doesn't timeout.


---
utils.c | 65 ++++++++++++++++++++++++---------------------------------
1 file changed, 27 insertions(+), 38 deletions(-)
diff --git a/utils.c b/utils.c
index 84cb570..b28107d 100644
--- a/utils.c
+++ b/utils.c
@@ -57,6 +57,10 @@
static struct {
int fds[2];
FILE *fps[2];
+
+ int timeout;
+ int timeouted;
+ pid_t pid;
} _child_reader;
static inline char *
@@ -304,6 +308,9 @@ read_child(void *arg)
fwrite(buf, (size_t)n, 1, _child_reader.fps[1]);
}
+ /* Child output reset alarm */
+ alarm(0);
+ alarm(_child_reader.timeout);
I looked at https://linux.die.net/man/2/alarm
I don't think alarm(0) is necessary, but it is fine.

}
fflush(_child_reader.fps[0]);
@@ -335,45 +342,28 @@ run_child(char *run_ptest, int fd_stdout, int fd_stderr)
/* exit(1); not needed? */
}
-static inline int
-wait_child(pid_t pid, int timeout, int *timeouted)
+static void
+timeout_child_handler(int signo)
{
- struct timespec sentinel;
- clockid_t clock = CLOCK_MONOTONIC;
- int looping = 1;
+ _child_reader.timeouted = 1;
+ kill(-_child_reader.pid, SIGKILL);
+}
+static inline int
+wait_child(pid_t pid, int timeout)
+{
int status = -1;
- int waitflags;
-
- if (clock_gettime(clock, &sentinel) == -1) {
- clock = CLOCK_REALTIME;
- clock_gettime(clock, &sentinel);
- }
- *timeouted = 0;
+ _child_reader.timeout = timeout;
+ _child_reader.timeouted = 0;
+ _child_reader.pid = pid;
- while (looping) {
- waitflags = WNOHANG;
+ /* setup alarm to timeout based on std{out,err} in the child */
+ alarm(timeout);
- if (timeout >= 0) {
- struct timespec time;
-
- clock_gettime(clock, &time);
- if ((time.tv_sec - sentinel.tv_sec) > timeout) {
- *timeouted = 1;
- kill(-pid, SIGKILL);
- waitflags = 0;
- }
- }
-
- if (waitpid(pid, &status, waitflags) == pid)
- looping = 0;
-
- clock_gettime(clock, &sentinel);
-
- if (WIFEXITED(status))
- status = WEXITSTATUS(status);
- }
+ waitpid(pid, &status, 0);
+ if (WIFEXITED(status))
+ status = WEXITSTATUS(status);
return status;
}
@@ -438,7 +428,6 @@ run_ptests(struct ptest_list *head, const struct ptest_options opts,
pid_t child;
int pipefd_stdout[2];
int pipefd_stderr[2];
- int timeouted;
time_t sttime, entime;
time_t duration;
int slave;
@@ -477,6 +466,7 @@ run_ptests(struct ptest_list *head, const struct ptest_options opts,
close(pipefd_stdout[1]);
break;
}
+ signal(SIGALRM, timeout_child_handler);
fprintf(fp, "START: %s\n", progname);
PTEST_LIST_ITERATE_START(head, p)
@@ -527,8 +517,7 @@ run_ptests(struct ptest_list *head, const struct ptest_options opts,
fprintf(fp, "BEGIN: %s\n", ptest_dir);
- status = wait_child(child, opts.timeout, &timeouted);
-
+ status = wait_child(child, opts.timeout);
entime = time(NULL);
duration = entime - sttime;
@@ -538,11 +527,11 @@ run_ptests(struct ptest_list *head, const struct ptest_options opts,
rc += 1;
}
fprintf(fp, "DURATION: %d\n", (int) duration);
- if (timeouted)
+ if (_child_reader.timeouted)
fprintf(fp, "TIMEOUT: %s\n", ptest_dir);
if (opts.xml_filename)
- xml_add_case(xh, status, ptest_dir, timeouted, (int) duration);
+ xml_add_case(xh, status, ptest_dir, _child_reader.timeouted, (int) duration);
fprintf(fp, "END: %s\n", ptest_dir);
fprintf(fp, "%s\n", get_stime(stime, GET_STIME_BUF_SIZE, entime));
--
2.31.0

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